Since discovered in 1980s, the quantum dots have attracted intensive attention from the scientific research field and the industrial field. Compared with the conventional fluorescent material, the fluorescence of quantum dots have the advantages of narrow fullwidth at half maxima, small particle size without scattering loss, size-tunable emission color and the like. Thus, quantum dots are widely regarded as having a promising application prospect in the fields such as display, illumination and biological fluorescent labeling. A large amount of manpower and material resources have been invested into the research on quantum dot materials in various countries. Accordingly, the photoelectric performance of the quantum dots is improved continuously, and prototype devices in the related fields have emerged. The application of quantum dots as the fluorescent material in the display field is regarded as the first breakthrough in the application fields of quantum dots. Since 2014, Samsung Electronics, LG and TCL have launched a variety of quantum-dot TV sets. This indicates a significant growth rate. Many institutions hold an optimistic attitude toward the application of quantum dots as the display devices, LEDs and the like. However, before the quantum dots are really applied as an excellent fluorescent material and become a novel material beneficial to mankind, there are still many basic scientific problems to be solved. Among those problems, the “stability of quantum dots” has been plaguing many scientists and has become one of the bottlenecks restricting the development of quantum dots. The stability of quantum dots in other application fields such as solar cells, biomarkers and environmental pollution treatment also becomes a great challenge.
At present, there are mainly three methods for improving the stability of quantum dots. (1) Core-shell quantum dots are prepared so that the stability is improved. However, the improvement to the stability of quantum dots is limited by only increasing the thickness of the shell. (2) The stability of quantum dots is enhanced by coating them with silicon dioxide or polymer. However, these methods have a common deficiency that the surfaces of quantum dots will be damaged during the coating process and the photoluminescence quantum yield of the quantum dots are thus reduced. (3) By preparing quantum dots doped with a passivating element, the stability of quantum dots may be improved to some extent. Therefore, improving the stability of quantum dots becomes a problem to be solved urgently.